Abstract
By studying the molecular basis of cold response in plants adapted to some of the world’s coldest biomes, we can gain insight into the evolution of cold tolerance - an important factor in determining plant distributions worldwide.
Although cold tolerance in temperate plants have been extensively studied, little is known about the evolutionary changes needed to transition from temperate to the more extreme polar zones.
Here, we conducted a time series experiment to examine the transcriptional responses of three Arctic Brassicaceae to low temperatures. RNA was sampled before onset of treatment, and after 3h, 6h, and 24h with 2 °C. We identified sets of genes that were differentially expressed in response to cold and compared them between species, as well as to published data from the temperate Arabidopsis thaliana.
We found that the cold response is highly species-specific. Among thousands of differentially expressed genes, ∼200 genes were shared among the three Arctic species and A. thaliana, and only ∼100 genes were specific to the three Arctic species alone. This pattern was also reflected in the functional comparison.
Our results show that the cold response of Arctic plant species has mainly evolved independently, although it likely builds on a conserved basis found across Brassicaceae. The findings also confirm that highly polygenic traits, such as cold tolerance, may show less repeatable patterns of adaptation than traits involving only a few genes.
Competing Interest Statement
The authors have declared no competing interest.